Bugfix that addresses issues with the Juggler install in jug_xl

Bugfix addressing issue using the Cairo backend to matplotlib

Bugfix, addresses issue where libQT5Core was causing issues on older Linux kernels

Fix issue with stripped python libraries.

Added gitlab-runner.

Update base container, Spack version and misc. software packages (most notably DD4hep & GEANT4).

Added Mad-X to the container

Add `opencascade` to the container

Added GNU parallel to the container.